Curious about Mercedes' steering geometry!

ThisIsWeird

Hi.

Seeing a parked Merc yesterday with its front wheels turned outwards reminded me that I've been curious about what form of steering geometry they use that seems so different to every other make!

Have a look - the wheel leans outwards at an astonishing positive camber when turned. What the?!

forgotmyname

Possibly had work done and not the tracking so it will wear the tyres out fast. Or it's been lowered which may push the wheels
out on that car and not noticed or not bothered or it's deliberate and will scrub tyres super fast but they think it looks cool and
spending hundreds on tyres is just a consumable like fuel.

Every 2nd tankful fit new tyres.  Same as those that lower their cars to the bumpstops so it does not handle properly and they
cannot put any load into the car because it crsushes the bumpstops.  MOT guy failed one where every bumpstop mount was
cracked and required extensive welding.

Goudy

Steering geometry is always a comprise.

The car has to track straight and stable on the straight and then be able to perform stable cornering.
And it has to do all this at different speeds.

The aim is to keep the tyres flat to the road as much as possible under all conditions yet still keep the stability in all conditions.

One needs a different set of geometry than the other and they do tend to interfere with each other.

Mercedes F1 introduced a dual axis steering set up a few years ago (that got banned).
This allowed the driver to change the toe angles, which effected the camber angles on the move.
This changed the steering angles between cornering stability/speed and straight line stability/speed without one compromising the other too much.

You got a near perfectly straight toe on the straights, with little tyre scrub for high speed straights, then pushed the toe out and camber over for the high speed corners.


The far reaches, ie at the ends of the steering rack tend to be the most comprised as most people don't really spend miles and miles at any great speed with the steering hard over to one side or the other, so the wheels can look a bit odd when you notice a car parked up with the steering over to one side.

You do get some tyre scrub, but it tends to be small, again you don't usually drive all day with them right over to one side.

The tighter the turning circle, the more pronounced it angles tend to look when hard over at the end of the rack.

Some owners set their cars up to to get an advantage one way or the other that obviously comprises the rest of the steering.

Drifters will try and set the cambers and toe up so the car is more stable with the steering hard over as they do actually spend a lot of time with the steering on full lock at high speeds. 
By doing this it compromises the straight line stability, but that's not what drifters need. 

Others might think they are on street drifting gods and set their road cars to a similar spec, mainly because they think it looks good.

Drag racers aren't bothered about steering, they just want it to go straight very quickly, so they set the geometry for straight line stability.
Venture too far off straight ahead and they'll be hopeless.

daveyjp

You don't say which model, but the saloon Mercs are rear wheel drive, with no drive shafts on the front wheels more camber is possible.

400ixl

Could also have been one of the ones with air suspension which can look odd at times when parked up.

The geometry on the front end of the Mercedes I owned until earlier this year was not really any different to any other car out there with similar sized low profile wheels.

ThisIsWeird

Thanks for your replies, folks.

No idea of the specific model, but it's something I have noticed on many Mercs - every one with their wheels pointed out. I've also seen it when they are driving at low speed and turn a corner.

I doubt it's a customising feature, as they were 'sensible' cars, not boy-racers!

Yes, they could be RWD models, but I haven't noticed the same with BMW.

Have a look he next time you see one parked up - if its wheels are turned. Really very different to other vehicles.

I'll take a photo next time too!

njkmr

I have a Merc and had a few others previously. I think it is designed in to help with manouverability. It allows the car to turn in a smaller circle than normal . Better when parking etc or turning in the road.